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<title>Childbirth: Wait to Restart the Pill, C.D.C. Says</title>
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The <a href="http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6026a3.htm?s_cid=mm6026a3_w">new recommendations</a>, by the Centers for Disease Control and Prevention, are more restrictive than guidelines issued last year and are similar to recommendations made in 2010 by the World Health Organization.        </p><p>
Women are far more likely to develop a blood clot in the weeks after delivery than nonpregnant women of reproductive age who have not just had a baby, several studies have shown. The risk declines rapidly after 21 days but does not return to normal until 42 days after delivery.        </p><p>
Birth control pills that include both <a href="http://topics.nytimes.com/top/news/health/diseasesconditionsandhealthtopics/estrogen/index.html?inline=nyt-classifier" title="Recent and archival health news about estrogen." class="meta-classifier">estrogen</a> and progestin also increase the risk of blood clots in the deep veins (venous thromboembolism). Women who are breast-feeding may want to avoid hormonal contraceptives because they can interfere with <a href="http://health.nytimes.com/health/guides/nutrition/breastfeeding/overview.html?inline=nyt-classifier" title="In-depth reference and news articles about Breastfeeding." class="meta-classifier">lactation</a>, the C.D.C. said.        </p><p>
The guidelines were published in the C.D.C.’s Morbidity and Mortality Weekly Report on Friday.        </p>

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